REGION-BASED IMAGE-CODING USING POLYNOMIAL INTENSITY FUNCTIONS

The vast majority of coded images are real-world images. These images consist of distinct objects within a scene, where each object has its own reflective, textural and lighting characteristics. Region-based im age coding encodes these images by partitioning the scene into objects , and then describing each object's characteristics using a set of par ameters, The paper uses orthonormal polynomial functions to describe t he lighting and reflective characteristics of each object. The coeffic ients of these polynomials are coded with linear quantisers that have their decision boundaries spaced according to rate-distortion consider ations. The textural component of each object is coded using vector qu antisation of the autocorrelation coefficients of the residual. The pa rtitioning of the image into distinct objects is achieved with a segme ntation algorithm which attempts to maximise the rate-distortion perfo rmance of the encoding procedure as a whole. In doing so, the segmenta tion algorithm partitions the image into distinct objects as well as p roviding estimates for the optimal bit allocations among the polynomia l coefficients. Results generated by this method show reconstructions with quality superior to other region-based methods, both objectively and subjectively.